Current regulator for electric lamps



July 9, 1929. c, wElCHELT 1.720.501

CURRENT REGULATOR FOR ELECTRIC LAIIPS Filed March 29, 1926 INVEN TOR.

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Patented July 9, 1929.

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UNITED STATES rnrenr orr ce.

CARL L. WEICI-IELT, or PHILADELPHIA, PENNs-YLvANimnssIeNoR TO wmr 00M- PAZNY, OEPHILADELPHIA, PENNSYLVANIA, A coaroa-A'rroN or AINE.

CURRENT REGULATOR FOR ELECTRIC LAMPS.

Application filed March 29, 1926. Serial No. 98,171.

My present invention relates to attachments for incandescent lamps by means of which the flow of current to the filament may be regulated and the intensity or candle power of the light produced thereby controlled and it has-for an object the production of a current reducing devicefor attachment to incandescent lamps in which a retatable rheostat ring is so secured to a standard socket plug and a lamp receiving socket that the individual circuit members of the plug and lamp socket are maintained rigidly in electrical contact'with each other.

Another object is the provision of a current reducing device including a plug, a

socket and a tubular rheostat ring rotatable around the socket, in which a sliding con-- tact arrangement is provided which insures the maintenance of a positive and efficient engagement of the stationary by the moving contacts. I a

A further object of the invent-ion is to provide a novel arrangement of the brushes and rheostat terminals on the stationary and movable parts whereby the control of cur-.

resistance terminals, one spring beingcorb nected to the center pin ot the plug and the other to the socket center contact." With this construction, the use of the rheostat shell as an element in the electrical circuit is unnecessary and all the .various elements in the electrical circuit may bereadily concealed and so protected as to prevent tampelw ing with them. 7

Another feature of the invention comprises an improved bearing for the rheostat ring comprising an annular flange extending inwardly from the inner shellof the ring and cooperatingto form a ournal connection between the ring, the plug and. the socket, with a similarly shaped annular shoulder piece adjacent the closed end of the socket. Vith such an arrangement, the rheostat ring is free to rotate 1n e ther dlrection around the socket anda positive engagement is assur'ed' between the stationary brushes and the rotatable terminals. I v The invention will be morethoroughly understood with theaid of the description to follow in connection with theaccompanying drawingsin which the same reference characters designate like parts and in which: Fig. l is an elevation of a lamp andysocket with, a device embodying the present invention interposed between the two.

Fig. 2 is a cross sectional view in elevation of the structure shown in Fig. 1. Fig. 3 is a cross-sectional view taken along the line 3 3 of Fig. 2. r 1 Fig. 4 is a bottom View of the plug showing the spring contacts in place. i

Fig. 5 is a horizontal sectional view looking downwardly on the line 5 -5 of Fig.2 with the socketremoved from the plug and the spring wipers in place. p

6 is a similar sectional view onthe line G G of Fig. 2. I.

Fig. 7 is an enlarged sectional view of the'rheostat ring taken alongthe line 7* of Fig. 2. i i

Fig. 8 isra diagrammatic viewvshow ing the rheostat contacts and the connections of the rheostat coils therewith with the layers of insulating material removed.

Figs..9, 10 and 11, are viewsin elevation of the rheostat contacts. I

Figs. 9, 10? and l lflare side'views of the contacts shown in Figs. 9, 1 0 and 11,. re-

spectively with the resistance coils in section.

Av lamp reducer or dimmer constructedin accordance 3 with my invention comprises plug and socket members 12 and --13 respectively adapted to form a connection between an electric lamp'23 and the terminal socket of an electric fixture 24, and a tubular rheostat ring, composed of inner and outer shells 15 and 16 enclosing a resistance unit 17 embedded in-a mass of insulating material18 and having terminals-19, 20, 21 and 22, exposed atone end, interposed betwee theplug and socket members.

is preferably formed in two parts 27 and 28 held together by the screw 29 threaded into the pin; 26. To prevent rotation of the parts 27 and 28 relative to each other, the

upper part 27 is provded with a non-circular projection 30 which fits into a similarly shaped groove 31 in the lower member 28. The metal casing 25 may be held in position around the end of the upper member 27 by partially closing the lower end thereof so that it will fitaround the projection 30 and engage the shoulders 32 and 33 surrounding the latter. By this arrangement of parts, it will be obvious that rotation of the casing 25 relative to the member 27 1s prevented. However, since too closely restricting this fitting between the metal stamping and molded insulating composition would curtail commercial production, a further means for preventing rotation and facilitating assembly of the parts is provided by forming on the closed end of the casing 25' a number of embossed por tion 34 which are seated within correspondingly shaped recesses 35 in the lower member 28 of the plug, as shown in Fig. 6.

On its lower surface, the member 28 is formed with a pair of semi-symmetrically arranged cylindrical extensions 36 which are separated to provide a slot or groove and projecting therefrom is a pair of sim ilarly shaped non-cylindrical extensions 37. These latter extensions 37 engage the sides of an aperture in the end of the socket shell 13 to prevent rotary movement of the plug relative to the socket, and the closed portion of said end lies parallel and in proximity to the ends of the extensions 36. This arrangement of parts is made secure by means of' screws 38 and 39'extending through the bottom of'the socket 13, plug members 27 and 28, and into the bottom wall of the plug casing 25.

The center contact which is commonly associated with an electrical socket shell is represented herein in the form of a spring contact 40ha-ving a finger portion extending into the slot between the extensions 36 and a depending portion extending through the aperture in the bottom of the shell to. make contact with the center or end terminal of an incandescent lamp base.

In the general form of device to which this invention relates, the desired current reduction is produced by a rotatable rheostat having terminals which successively engage a stationary contact or wiper to complete a, series circuit including a source of potential andthe lamp filament. In accordance with a feature of the present invention, the stationary contact arrangement comprises a pair of diametrically disposed spring wipers '41 and 42 on the member 28 encircling the extensions 36 at opposite ends 29 of the plug, and the latter lying beneath the centersocket contact 40, which latter parts are held together and attached to the plug member by the rivet 45.

It will be seen that by connecting the wipers in the manner described, a series circuit is established which includes the center pin 26, spring contact 41, a portion of the resistance coil 17, depending upon the rheostat terminals in engagement with the wipers 41 and 42, wiper 42, rivet 45, contact 40, the lamp filament, the shell 13, screws 38 and 39 and the plug shell 25.

In'order to' obtain the advantages of a sliding contact arrangementand produce a positive engagement between the moving and stationaryc'ontacts, it is preferable that the mechanical relation between the rheostat ring 14, the socket 13 and the plug mem- V 46 which is adapted to receive an inwardly extending flange 47 on the upper end of the inner rheostat shell 15 by which the ring 14 is supported. overlying the flange 47. is

a dish-shaped washer 48. In assemblying these parts the socket 13 is placed within the rheostat ring with its bottom projecting within the flange 47 and the washer 48 being then applied, the bolts 38 are secured in position. v

The construction of the resistance ring or unit per se may assume various forms and a form which has been found to be especially satisfactory is the one shown herein. Referring to Figs. 7 to 11 inclusive, a num ber of contact bars,'four being shown, as

' 19, 20, 21,- and 22, are arranged in alinement concentric to the axis of the ring with their upper ends exposed. One of the end bars as 19 is sufficiently longer than the others .to permit its simultaneous engagement by both the wipers 41 and 42, and the latter it will be'noticed in Figs. 4 and 5 have their free ends extending toward each, other.

Each of the bars 19,20, 21, and22 is provided with outwardly extending ears I 49 which serve as binding posts to which the resistance coils are connected. These ears may be formed integral with the terminal bar or may be thin metallic strips secured to the bars by means of rivets 49 as shown.

Resistance coils 50, 51 and 52 are wound cylindrically with insulating layers 53 separating the coils and bars and interposed between each individu-al turn of wire. The opposite ends of successive coils are secured to the ears 49 on the same contact bar or terminal and the free ends of the initial and final coils 50 and 52 are then bound to the ears 49 of separate bars, 19 and 22 respectively. With such a construction, the terminalbars serve bothas contacts for the rheostat and as connecting links between the adjacent ends of superposed coils and it is thereby possible to separately insulate each stage of resistance and at the same time employ contacts lying in the circumference of the same circle. It will be understood that the values of the resistance in any one coil, or the number of coils, may be varied as desired and will be determined by the conditions presented in any given. instance. By reference to Fig. 8, showing a diagrammatic view of the resistance'contact construction with the insulation removed,

and Figs. 9 and 9 10 and 10, and 11 and 11?, illustrating in detail the structure of contacts 22, 20 and 19 respectively, a thor ough understanding of the construction of the rheostat may be readily obtained.

Various means of rotating the rheostat ring 14 may be employed and in the drawings I have shown a cord or flexible chain 54 secured between its ends to a staple 55 carried by the shell 16, and leading from both sides of said staple through eyes 56 56 on the yoke 57 held in the slotted upper portion of member 28 by the extension 30 of member 27. These eyes give a proper lead for the cords or chains 54 and transform the vertical pull upon the cords to the necessary tension to rotate the rheostat ring. The rotational movement of the ring 14 will be limited to approximately a half revolution by the staple 55 contacting on opposite sides with the eyes 5656. The point of attachment of the staple should bear such a relation to the contacts 19 to 22 that the successive engagement of the contacts 19 to 22 by spring contact 41 is permitted simultaneous with the engagement'of contact 19 by spring contact 42.

Upon. rotation of the ring, such as by pulling one end orthe other of chain 54, the contacts 20, 21, and 22 are brought successively into engagement with the spring 41 while the longer contact 19 is maintained in engagement with the spring 42. Electrical circuits will be established through the pin 26 to the spring 41 and thence through one of the contacts 20,21, or 22 and a portion of the resistance unit to contact 19 and spring 42. Since the spring 42 is secured to the socket-center spring 40, current then passes through spring40to the center terminal of the lamp, through the filament, and into the sheath of the la-mpbase and the socket'18; from the socket, the electrical circuit continues through the screws 38 and 39 and into the shell 25, thereby completing a circuit including in series a resistance and the lamp filament. By rotating the rheostat ring to cause the bar 19 to engage both springs 41 and 42 the rheostat resistance unit will be short-circuited and the lamp will burn with full brilliancy.

From the foregoing it will be observed that I have provided an arrangement of parts whereby. no portion of the rheostat shell is included in the circuit, hence there is no outside or exposed portion of the shell which acts at any time as a conductor;- in other words when any portion of the rheostat windings is acting as a resistance such. resistance is included entirely in one side of the circuit independently of the rheostat shell. Likewise, when the winding is shortcircuited by the engagement of the two brushes 41 and 42 with the single contact 19, no current passes through said shell. It is, of course, immaterial in which side of the circuit the brushes are located, but an advantage is obtained in arranging them in that part of the circuit extending through the center of the plug and lamp socket, as these parts lend themselves readily to anarrangement whereby the center pin in the plug and the center lamp contact can be properly insulated 'from each other and from the plug shell and lamp socket shell, and also connected one to each brush and the latter firmly mounted on the stationary part of the regulator.

From the arrangement of parts described, it' will be seen that the device comprises a simple construction which may be easily assembled, in which the various members are maintained in rigid mechanical and electrical contact with each other, in-which the rheostat ring may beeasily rotated to produce a firm, positive engagement of the stationary contacts with the rotating contacts, and in which all electrically conducting members are protected from possible injury by contact with extraneous articles.

In accordance with the provisions of the patent statutes the principle of the invention has been described, and illustrated by the portrayal of a structure which in practice has proved to be a satisfactory embodiment v thereof, but it is desired to have it understood that the structure shown is merely illustrative, and that the invention maybe carried out in other ways. I

The invention having been described, what is claimed as new and desired to be secured V by Letters Patentis as follows 1. In an electric lamp attachment, the combination with a lamp socket comprising a posed at the upper end center contact, and a plug member for attachment to a socket comprising a conducting outer shell and a center conducting pin, said center contact and pin being in-- sulated from each other, of a rotatable rheo stat ring surrounding the socket comprising a plurality of resistance elements and brushes connected with the center pin of the plug and with the center contact of the socket and co-operating with the resistance elements.

2. In an electric lamp fixture, the combination with a plug of insulating material having an outer casing adapted to fit a lamp socket and a conducting center pin, and a lamp socket shell connected in circuit with the casing of the plug, of a center lamp contact in the shell independel'lt of said center pin, rotatable tubular rheostat ring surrounding the shell and having resistance winding contacts exposedat one end, and a pair of spring contact elements supported on the plug and connected one to each of said center contacts and engaging the rheostat contacts.

3. In an electric lamp attachment, the combinationwith a plug oi? insulating material having a metallic band encircling one end and adapted to lit a lamp socket, a metallic center pin extending through the plug, and a lamp socket shell secured to the plug and connected to said band, of a center lamp contact carried by the plug and insulated from said center pin, a rotatable cylindrical resistance ring encircling the shell and having resistance winding terminals extending at one end thereof, spring contacts secured to the plug, one in electrical contact with said pin and the other in engagement with the center lamp contact, and both arranged to engage rheostat terminals to complete the lamp circuit through said center contacts.

t. In an electric lamp fixture, the combination with. an insulating plug having a non-circular projection on its lower end, a metallic shell encircling theplug and a center pin extending through the plug, a lamp socket shell having a bottom provided. with an aperture fitting over the projection, of a revolvable rheostat ring surrounding the lamp socket shell comprising a plurality of resistance windings having terminals exot the ring, a support ing flange on said ring extending between the plug and the bottom of said shell, spring brushes depending from the lower side of the plug and engaging said terminals, one brush being connected to the center pin of the plug and the other to the lamp center contact, and means for rigidly connecting the lamp socket shell to the plug shell to establish a circuit connection between them.

5. A current reducer for electric lamps comprising a plug portion for attachment to a socket, a socket for receiving'a lamp, a

rotary rheostat ring surrounding the socket and having a plurality of resistances pro ided with terminals disposed circularly at one edge of the ring, a pair o't'brushes carried on the plug portion and cooperating with said terminals, one of the end terminals being longer than the others, and the brushes being so disposed thereto that in one position of adjustment they both engage therewith and upon relative rotation of the plug and ring one oi the brushes will engage the other terminals successively.

6. A current reducer for electric lamps comprising a plug portion for attachment to a socket, a socket for receiving a lamp, a rotary rheostat ring surrounding the socket and having a plurality of resistances provided with circularly disposed terminals on the upper edge of the ring, a pair of contact brushes on the bottom of the plug having their free ends located relatively to each other in spaced relation and cooperating with said terminals, one of the latter at one end of the series of terminals being of sufficient length to connect the two brushes in one position of adjustment and retain con tact with one ot the brushes durlng relative rotary movement of the plug and ring whlle the. other ln'ush successively engages the other terminals.

7. A. current reducer for electric lamps comprising a plug portion for attachment to a socket, said plug having a transverse bottom slot, a socket for receiving a lamp depending t'rom the plug, a rotary rheosta-t ring surrrnmding the sockctand rotatably secured on the bottom of the plug, having successively disposed resistance coils each provided with a separate terminal, one end terminal being of greater length than the others, brush .members having finger portions lying in said. slot and having free ends extending circularly and engaging the terminals.

8. A current reducer for electric lamps comprising a plug portion for attachment to a socket embodying a shell and a. central contact pin, said plug having a transverse bottom slot, asocket for receiving a lamp depending from the plug and in electrical connection with said shell, a rheostat ring surrounding the socket having successively disposed resistance coils each provided with a separate terminal, one of the end terminals being ot'greaterlength than the others, a brush member having a linger portion lying in saidslot and in electricalv contact with said center pin, a second brush having a portion lying in said slot, said brushes having the combination with a lamp socket plug comprising a center contact and an outer shell, a lamp socket depending from the plug and in electrical contact with said shell, of a rheostat ring surrounding the socket and having an inwardly extending flange extending between the bottom of the plug and the socket to support said ring against axial movement while permitting rotation thereof, said ring embodying resistance windings having contacts, and circuit contacts on the plug co-operating with those on the ring.

10. In a device of the character described, the combination with a rheostat ring having a resistance winding and contacts therefor projecting at its upper edges, an inner tubular wall for said ring having an inwardly extending flange at its upper edge and a lamp socket therein having a bottom provided with a bearing surface for said flange, of a retaining member fitting against the bot tom of the socket and extending over said flange, a plug of insulating material resting against said member and securing means extending through the bottom of the socket, the retaining member and the plug and contact members carried on the bottom of the plug and co-operating with the contacts of said rin 11. In a device of the character described, the combination with an insulating plug and a brush carrying member, said parts having on their contiguous faces inter-fitting dentures, a lamp socket shell surrounding the plug having bottom portions extending between said faces, a center lamp contact on the lower side of the brush carrying member, and a center contact on the plug, of alamp socket depending from the brush carrying 'member, devices securing the shell to said member, and providing circuit connections between it and the shell on the plug, a rheostat ring surrounding the lamp socket shell and revolubly supported on the brush carrying member and having resistance windings provided with a plurality of contacts and a pair of brushes mounted on the brush carrying member and co-operating with said contacts, and connected respectively to said center lamp contact and the center plug contact.

12. In a device of the character described, the combination with an insulating plug and a brush carrying member, said parts having on their contiguous faces inter-fitting dentures, a lamp socket shell surrounding the plug having bottom portions extending between said faces, a member having guides at opposite sides of the device and provided with an intermediate portion extending between the plug and brush carrying member and co-operating with said dentures, a center contact on the plug, and a center lamp contact on the brush carrying member, of a lamp socket having a bottom abutting the brush carrying member, a device securing the shell to said member and forming a circult connection between said shell and the plug shell, a rheostat ring revolubly mounted with respect to the lamp shell and said brush carrying member and comprising resistance windings having a plurality of contacts, a pair of brushes on the brush carrying member co-operating with said contacts and connected respectively to the center lamp contact and the center plug contact, and flexible operating means attached to the rheostat ring and extending through the guides of said guide member.

18. In a device of the character described, the combination with a lamp socket plug of insulating material, a lamp socket in axial alinement therewith having a bottom secured against the bottom of the plug and provided with a peripheral oilset, and a washer lo-s cated between the bottoms of said parts having its edge extending over said offset and forming a channel between it and said socket of a rheostat ring surrounding the socket provided with an annular supporting flange extending into said channel and revolubly supporting the ring, and means for securing said plug, washer and socket together to sup port the rheostat in assembled position with said parts.

This specification signed and witnessed this 25th day of March, 1926.

CARL L. WEICI-IELT. 

